Wheel hub

ABSTRACT

A wheel bearing of a motor vehicle, with a wheel hub arranged rotatably on a transmission axle via at least one pair of rolling bearings and having a flanged surface for at least one running wheel. A brake disc is connected to the wheel hub. The wheel hub is of two-part or multi-part design and a first wheel-hub part is connected to a first rolling bearing and/or to a second rolling bearing and a second wheel-hub part is connected to the brake disc.

[0001] This application claims the priority of German Patent DocumentNo. 101 61 206.0, filed Dec. 13, 2001, the disclosure of which isexpressly incorporated by reference herein.

BACKGROUND AND SUMMARY OF THE INVENTION

[0002] The present invention relates to a wheel bearing of a motorvehicle, with a wheel hub arranged rotatably on a transmission axle viaat least one pair of rolling bearings and having a flanged surface forat least one running wheel, and with a brake disc connected to the wheelhub.

[0003] There is already a wheel mounting of a driven axle, with a hollowaxle body which receives the wheel loads and on the respective outer endof which is seated, fixed axially, at least one rolling bearing carryinga wheel hub with at least one brake disc or brake drum, to which wheelhub is flanged a drive-shaft flange of a drive shaft projecting out ofthe respective outer end of the hollow axle body, the drive-shaft flangeand the wheel hub and also the wheel hub and the flange or flangedregion of the brake disc or brake drum having in each case contactingmounting surfaces.

[0004] The object on which the present invention is based is to designand arrange a wheel hub in such a way that simple mounting of the brakedisc and of the rolling-bearing arrangement is ensured.

[0005] The object is achieved, according to the present invention, inthat the wheel hub is of two part or multi-part design, a firstwheel-hub part being connected to a first rolling bearing and/or to asecond rolling bearing and a second wheel-hub part being connected tothe brake disc. What is achieved thereby is that, when the brake disc isbeing changed, there is no need to also remove the bearing arrangement.The brake disc can be demounted together with the second wheel-hub part,while the first wheel-hub part having the bearing arrangement remains onthe transmission axle designed as an axle journal. This affordsadvantages even during the assembly of the wheel bearing, because, forexample, the bearing arrangement can be prefabricated, so that later,during line assembly, all that is necessary is a substantially lesstime-consuming attachment or screwing-on of the second bearing parttogether with a brake disc. It is also conceivable to screw-connect thebrake disc additionally, independently of the wheel hub, in a similarway to motorcycles, so that only the brake disc may be mounted,independently of the wheel hub.

[0006] For this purpose, it is advantageous that the brake disc has aflanged part forming an axial bearing or a flanged surface and a radialbearing and be designed as a cylindrical basic body, the inside diameterof the flanged part and of the brake disc being at least equal to theoutside diameter of the first wheel-hub part. This ensures that thebrake disc, together with the second bearing part, can be separated fromthe first bearing part or, during mounting, can be slipped over thefirst wheel-hub part. The second wheel-hub part is in this case arrangedin front of the first wheel-hub part, so that the latter can likewise bedrawn off outwards after the release of the screw connection.

[0007] According to another embodiment, an additional possibility isthat the basic body of the brake disc is formed by the second wheel-hubpart and the radial bearing is formed by the first wheel-hub part and/orby the second wheel-hub part, the flanged surface of the brake discbeing oriented radially to, and the basic body coaxially to, awheel-bearing center axis. This ensures a simple and rapid production ofthe flanged surfaces.

[0008] Furthermore, it is advantageous that the first wheel-hub part hasa flanged surface designed as a radial bearing and/or as an axialbearing for the second wheel-hub part, the first wheel-hub part beingconnected to the second wheel-hub part via a screw connection. Thislikewise ensures simple and rapid manufacture. The screw connectionserves at the same time for connecting a drive shaft to the wheel hub.

[0009] It is also advantageous, for this purpose, that the firstwheel-hub part and/or the second wheel-hub part are/is connected to thebrake disc via at least one fixing screw and/or via at least one bolt.The fixing screw serves in this case for the premounting of the secondwheel-hub part and the brake disc, so that these can be connected as astructural unit to the first wheel-hub part. A sufficient fastening ofthe brake disc to the second or else the first wheel-hub part isafforded by the bolt connection for the running-wheel connection.

[0010] Finally, according to a preferred embodiment of the presentinvention, there is provision for there to be provided at the outer endof the transmission axle an axle flange of a drive shaft, the axleflange being designed as a shaft flange and being connected to the firstwheel-hub part and/or to the second wheel-hub part via the screwconnection of the two wheel-hub parts. Both wheel-hub parts are thusconnected to the drive flange simultaneously via only one screwconnection.

[0011] It is particularly important for the present invention that thefirst and the second rolling bearing are connected at the outer end ofthe transmission axle to a prestressing element designed as an axle nutor are prestressed by the prestressing element. The bearing prestress ofthe rolling-bearing arrangement can thus be determined independently ofthe mounting of the brake disc.

[0012] It is also advantageous that the brake disc has a further radialbearing and/or a parking brake together with the axle journal, the ratioof the distances in the axial direction from an axial bearing to abrake-disc surface and from the axial bearing to the parking brake beingbetween 2:1 and 10:1. The brake disc surface is consequently arranged soas to be offset to the rear with respect to its fastening flange and isconnected in one piece to the fastening flange via a flanged part. Inaddition to the possibility of being able to arrange a parking brakewithin this flanged part, the cylindrical basic-body surface affords anadditional cooling surface for the brake disc.

[0013] In connection with the design and arrangement according to thepresent invention, it is advantageous that the individual bolts of thescrew connection are arranged on a part-circle of the size of the meancircumference of the wheel hub. The screw connection connects bothwheel-hub parts and by virtue of its rotationally-symmetricalarrangement can be handled simply and quickly.

[0014] Moreover, it is advantageous that, after the release of thebolting connection for the rim, the running wheel or the rim isseparated from the hub and, after the release of the screw connection ofthe shaft flange, the drive shaft, together with the second wheel-hubpart and the brake disc, is separated from the remaining part of thewheel bearing or of the first wheel-hub part. In this case, it isadvantageous that, after the release of the fixing screws, the brakedisc is separated from the second wheel-hub part and, after the exchangeof the brake disc, the latter is reconnected to the second wheel-hubpart by the fixing screws. The two parts are slipped onto the wheelbearing or the first wheel-hub part and are connected to this and to thedrive shaft by the screw connection. Only then is the running wheel,together with the brake disc, fastened via the bolt connection.

[0015] Other objects, advantages and novel features of the presentinvention will become apparent from the following detailed descriptionof the invention when considered in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIGURE 1 is a sectional view of a wheel bearing with a two-partwheel hub and brake disc in accordance with an embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0017] FIGURE 1 illustrates a wheel bearing 1 for a running wheel 10mounted rotatably on a transmission axle 2 designed as an axle journal.

[0018] Arranged on the stepped axle journal 2 are a first and a secondrolling bearing 8.1, 8.2 which are prestressed via an axle nut 19arranged at the outer end of the axle journal 2. The axle journal 2 has,for this purpose, an outer shoulder 2.1, against which the secondrolling bearing 8.2 or its bearing inner ring comes to bear via a spacerring 2.2.

[0019] The axle journal 2 is designed as a hollow profile and on itsright-hand side (according to FIGURE 1) adjoins an axle receptacle, notillustrated. Within the axle journal 2 is arranged a coaxial inner shaft20 which is designed as a drive shaft and which is connected to a wheelhub 3 via an axle flange 18 designed as a shaft flange.

[0020] Arranged rotatably on the axle journal 2 is a first wheel-hubpart 3.1 which is supported on the axle journal 2 via the pair ofrolling bearings. For this purpose, the first wheel-hub part 3.1 has aninner shoulder 3.5, against which in each case one of the two rollingbearings 8.1 and 8.2, or their respective bearing outer ring, comes tobear.

[0021] The first wheel-hub part 3.1 has outwardly a flanged surface 15which serves for receiving a second wheel-hub part 3.2. The flangedsurface 15 consists of two surface portions which run parallel to awheel-bearing center axis 7 and which form a radial bearing 12 and oftwo surface portions which run perpendicularly to the wheel-bearingcenter axis 7 and which form an axial bearing 13 for the secondwheel-hub part 3.2.

[0022] The first wheel-hub part 3.1 and the second wheel-hub part 3.2are connected releasably via a screw connection 14 arranged on a circleof holes, the axle flange 18 also being connected to the first wheel-hubpart 3.1 and the second wheel-hub part 3.2 by the same screw connection14.

[0023] The second wheel-hub part 3.2 has, in addition to the flangedsurface 15 matching the first wheel-hub part 3.1, a flanged surface 9for the wheel tire 10 or its rim 10.1 and a second flanged surface for aflanged surface 4.2 of the brake disc 4. In this case, the rim 10.1, thesecond wheel-hub part 3.2 and the flanged surface 4.2 of the brake disc4 are screwed together releasably via a bolt connection 17.

[0024] The brake disc 4 has, in addition to its actual brake-discsurface 4.1 provided with cooling bores, a cylindrical flanged partdesigned as a basic body 4.4, with the flanged surface thereof servingas an axial bearing 4.2 and with an inside or outside thereof serving asa radial bearing 4.3. The flanged surface relative to the secondwheel-hub part is provided at the end of the cylindrical basic body 4.4.The outside and inside of the cylindrical basic body 4.4 in this caseform, at least in the region of the flanged surface 4.2, the radialbearing together with the first and second wheel-hub parts 3.1, 3.2. Theinner or outer face serving as a radial bearing is arrangedperpendicularly to the flanged surface 4.2 and directly adjoins thelatter.

[0025] The flanged surface 4.2 is connected to the second wheel-hub part3.2 and the rim 10.1 via the bolt 17. The flanged part 4.4 is fixed inthe radial direction via an outer shoulder 3.6 of the first wheel-hubpart 3.1 and via the flanged surface or an outer edge of the secondwheel-hub part 3.2.

[0026] Between the brake disc 4 and the axle journal 2 is provided aparking brake 11 which is mounted on the axle journal 2 and which by anactuating device, not illustrated, generates a non-positive orfrictional connection with the inner surface of the brake disc 4 or thebasic body 4.4.

[0027] The foregoing disclosure has been set forth merely to illustratethe invention and is not intended to be limiting. Since modifications ofthe disclosed embodiments incorporating the spirit and substance of theinvention may occur to persons skilled in the art, the invention shouldbe construed to include everything within the scope of the appendedclaims and equivalents thereof.

What is claimed is:
 1. A wheel bearing of a motor vehicle, with a wheelhub arranged rotatably on a transmission axle via at least one pair ofrolling bearings and having a flanged surface for at least one runningwheel, and with a brake disc disconnected to the wheel hub, wherein thewheel hub is of two-part design with a first wheel-hub part connected toa first rolling bearing and/or to a second rolling bearing and a secondwheel-hub part connected to the brake disc.
 2. The wheel bearingaccording to claim 1, wherein the brake disc has a cylindrical basicbody forming a radial bearing and an axial bearing and is designed as aflanged part and wherein an inside diameter of the basic body and of thebrake disc is at least equal to an outside diameter of the firstwheel-hub part.
 3. The wheel bearing according to claim 2, wherein theaxial bearing of the brake disc is formed by the second wheel-hub partand the radial bearing is formed by the first wheel-hub part and/or bythe second wheel-hub part, and wherein a flanged surface of the brakedisc is oriented radially to, and the basic body, flanged part, isoriented coaxially to, a wheel bearing center axis.
 4. The wheel bearingaccording to claim 1, wherein the first wheel-hub part has a flangedsurface designed as a radial bearing and/or as an axial bearing for thesecond wheel-hub part, the first wheel-hub part being connectedreleasably to the second wheel-hub part via at least one connectionmember.
 5. The wheel bearing according to claim 1, wherein the firstwheel-hub part and/or the second wheel-hub part are/is connected to thebrake disc via at least one fixing element and/or via at least oneholding element.
 6. The wheel bearing according to claim 1, wherein anaxle flange of a drive shaft is connected to the first wheel-hub partand/or to the second wheel-hub part via a connection member.
 7. Thewheel bearing according to claim 1, wherein the rolling bearings have aprestressing element designed as an axle nut.
 8. The wheel bearingaccording to claim 2, wherein the brake disc has a second radial bearingand/or a parking brake together with the transmission axle designed asan axle journal, a ratio of a distance from the axial bearing to abrake-disc surface and from the axial bearing to the parking brake in anaxial direction being between 2:1 and 10:1.
 9. The wheel bearingaccording to claim 4, wherein individual bolts of the connection memberare arranged on a part-circle of the wheel hub, wherein said part-circlecorresponds to a mean diameter of the wheel hub.
 10. A method formounting a brake disc comprising the steps of: a) after releasing aconnection for a rim, separating a running wheel from a hub, b) afterreleasing a connection member of an axle flange, a drive shaft, togetherwith a second wheel-hub part and a brake disc, is separated from a firstwheel-hub part, c) after releasing a fixing member, the brake disc isseparated from the second wheel-hub part, d) fastening the brake disc tothe second wheel-hub part by the fixing member, e) slipping the brakedisc and the second wheel-hub part onto the first wheel-hub part andconnecting the brake disc and second wheel-hub part to the firstwheel-hub part and to the drive shaft by the connection member, and f)fastening the running wheel to the second wheel-hub part.
 11. A wheelhub for a motor vehicle, comprising: a first wheel-hub part connected toa rolling bearing; and a second wheel-hub part connected to a brakedisc; wherein the first wheel-hub part is releasably connected to thesecond wheel-hub part.
 12. The wheel hub of claim 11 wherein the firstwheel-hub part is disposed within the second wheel-hub part.
 13. Thewheel hub of claim 11 wherein the first wheel-hub part is disposedbetween the rolling bearing and the second wheel-hub part.
 14. The wheelhub of claim 11 wherein the first wheel-hub part is releasably connectedto the second wheel-hub part by a connection member.
 15. The wheel hubof claim 11 wherein the first wheel-hub part and the second wheel-hubpart both include an axial bearing surface and a radial bearing surface,wherein the axial bearing surface of the first wheel-hub part engagesthe axial bearing surface of the second wheel-hub part and wherein theradial bearing surface of the first wheel-hub part engages the radialbearing surface of the second wheel-hub part.
 16. A method for mountinga brake disc, comprising the steps of: separating a second wheel-hubpart from a first wheel-hub part wherein a first brake disc is connectedto the second wheel-hub part and wherein the first wheel-hub part isconnected to a transmission axle; removing the first brake disc from thesecond wheel-hub part; placing a second brake disc on the secondwheel-hub part; and connecting the second wheel-hub part and the secondbrake disc to the first wheel-hub part.
 17. The method of claim 16,wherein the second brake disc is the first brake disc.
 18. The method ofclaim 16 wherein the step of connecting the second wheel-hub part to thefirst wheel-hub part includes the step of disposing the second wheel-hubpart around the first wheel-hub part.